/*
  time.h - low level time and date functions
*/

/*
  July 3 2011 - fixed elapsedSecsThisWeek macro (thanks Vincent Valdy for this)
              - fixed  daysToTime_t macro (thanks maniacbug)
*/

#ifndef _Time_h
#define _Time_h

#include <Arduino.h>
#include <inttypes.h>

typedef enum {
  timeNotSet,
  timeNeedsSync,
  timeSet
} timeStatus_t;

typedef enum {
  dowInvalid,
  dowSunday,
  dowMonday,
  dowTuesday,
  dowWednesday,
  dowThursday,
  dowFriday,
  dowSaturday
} timeDayOfWeek_t;

typedef enum {
  tmSecond,
  tmMinute,
  tmHour,
  tmWday,
  tmDay,
  tmMonth,
  tmYear,
  tmNbrFields
} tmByteFields;

typedef struct {
  uint8_t Second;
  uint8_t Minute;
  uint8_t Hour;
  uint8_t Wday; // day of week, sunday is day 1
  uint8_t Day;
  uint8_t Month;
  uint8_t Year; // offset from 1970;
} tmElements_t, TimeElements, *tmElementsPtr_t;

// convenience macros to convert to and from tm years
#define tmYearToCalendar(Y) ((Y) + 1970) // full four digit year
#define CalendarYrToTm(Y)   ((Y)-1970)
#define tmYearToY2k(Y)      ((Y)-30) // offset is from 2000
#define y2kYearToTm(Y)      ((Y) + 30)

typedef time_t (*getExternalTime)();
// typedef void  (*setExternalTime)(const time_t); // not used in this version

/*==============================================================================*/
/* Useful Constants */
#define SECS_PER_MIN  ((time_t)(60UL))
#define SECS_PER_HOUR ((time_t)(3600UL))
#define SECS_PER_DAY  ((time_t)(SECS_PER_HOUR * 24UL))
#define DAYS_PER_WEEK ((time_t)(7UL))
#define SECS_PER_WEEK ((time_t)(SECS_PER_DAY * DAYS_PER_WEEK))
#define SECS_PER_YEAR ((time_t)(SECS_PER_DAY * 365UL)) // TODO: ought to handle leap years
#define SECS_YR_2000  ((time_t)(946684800UL))          // the time at the start of y2k

/* Useful Macros for getting elapsed time */
#define numberOfSeconds(_time_)  ((_time_) % SECS_PER_MIN)
#define numberOfMinutes(_time_)  (((_time_) / SECS_PER_MIN) % SECS_PER_MIN)
#define numberOfHours(_time_)    (((_time_) % SECS_PER_DAY) / SECS_PER_HOUR)
#define dayOfWeek(_time_)        ((((_time_) / SECS_PER_DAY + 4) % DAYS_PER_WEEK) + 1) // 1 = Sunday
#define elapsedDays(_time_)      ((_time_) / SECS_PER_DAY)                             // this is number of days since Jan 1 1970
#define elapsedSecsToday(_time_) ((_time_) % SECS_PER_DAY)                             // the number of seconds since last midnight
// The following macros are used in calculating alarms and assume the clock is set to a date later than Jan 1 1971
// Always set the correct time before setting alarms
#define previousMidnight(_time_)    (((_time_) / SECS_PER_DAY) * SECS_PER_DAY)                            // time at the start of the given day
#define nextMidnight(_time_)        (previousMidnight(_time_) + SECS_PER_DAY)                             // time at the end of the given day
#define elapsedSecsThisWeek(_time_) (elapsedSecsToday(_time_) + ((dayOfWeek(_time_) - 1) * SECS_PER_DAY)) // note that week starts on day 1
#define previousSunday(_time_)      ((_time_)-elapsedSecsThisWeek(_time_))                                // time at the start of the week for the given time
#define nextSunday(_time_)          (previousSunday(_time_) + SECS_PER_WEEK)                              // time at the end of the week for the given time

/* Useful Macros for converting elapsed time to a time_t */
#define minutesToTime_t(M) ((M)*SECS_PER_MIN)
#define hoursToTime_t(H)   ((H)*SECS_PER_HOUR)
#define daysToTime_t(D)    ((D)*SECS_PER_DAY) // fixed on Jul 22 2011
#define weeksToTime_t(W)   ((W)*SECS_PER_WEEK)

/*============================================================================*/
/*  time and date functions   */
int     hour();                 // the hour now
int     hour(time_t t);         // the hour for the given time
int     hourFormat12();         // the hour now in 12 hour format
int     hourFormat12(time_t t); // the hour for the given time in 12 hour format
uint8_t isAM();                 // returns true if time now is AM
uint8_t isAM(time_t t);         // returns true the given time is AM
uint8_t isPM();                 // returns true if time now is PM
uint8_t isPM(time_t t);         // returns true the given time is PM
int     minute();               // the minute now
int     minute(time_t t);       // the minute for the given time
int     second();               // the second now
int     second(time_t t);       // the second for the given time
int     day();                  // the day now
int     day(time_t t);          // the day for the given time
int     weekday();              // the weekday now (Sunday is day 1)
int     weekday(time_t t);      // the weekday for the given time
int     month();                // the month now  (Jan is month 1)
int     month(time_t t);        // the month for the given time
int     year();                 // the full four digit year: (2009, 2010 etc)
int     year(time_t t);         // the year for the given time

const String timeString();
const String timeString(time_t t);

time_t now(); // return the current time as seconds since Jan 1 1970
void   setTime(time_t t);
void   setTime(int hr, int min, int sec, int day, int month, int yr);
void   adjustTime(long adjustment);

/* date strings */
#define dt_MAX_STRING_LEN 9 // length of longest date string (excluding terminating null)
const String monthStr(uint8_t month);
const String dayStr(uint8_t day);
const String monthShortStr(uint8_t month);
const String dayShortStr(uint8_t day);

/* time sync functions	*/
timeStatus_t timeStatus();                                     // indicates if time has been set and recently synchronized
void         setSyncProvider(getExternalTime getTimeFunction); // identify the external time provider
void         setSyncInterval(time_t interval);                 // set the number of seconds between re-sync

/* low level functions to convert to and from system time                     */
void   breakTime(time_t time, tmElements_t &tm); // break time_t into elements
time_t makeTime(const tmElements_t &tm);         // convert time elements into time_t

#endif /* _Time_h */
